TWI825132B - Method for multi-connectivity - Google Patents

Abstract

A method for multi-connectivity between a plurality of base stations and user equipment includes estimating, at the user equipment, a first round trip time (RTT) taken in transmitting first data to a first base station, estimating, at the user equipment, a second RTT taken in transmitting second data to a second base station, and determining a size of the first data which is to be transmitted to the first base station, based on the first RTT and the second RTT.

Description

Methods for multiple connections

The inventive concept relates to wireless communications, and more particularly, to a method and an apparatus for partitioning data across multiple connections.

In wireless communications between user equipment and base stations, various techniques can be used to send larger amounts of data at higher speeds. For example, multi-connection may represent a process in which one user equipment communicates with two or more base stations. In multi-connection, data can be sent and/or received via multiple channels between the user equipment and two or more base stations, and therefore the data throughput can be increased and communication quality can be prevented from being degraded by poor quality channels. . In order to improve the efficiency of multiple connections, it is expected to efficiently distribute the transmission data to multiple channels.

The inventive concept provides a method and an apparatus for efficiently partitioning data in multiple connections.

According to an aspect of the inventive concept, a method for implementing multiple connections between a plurality of base stations and a user equipment is provided, the method comprising: estimating, at the user equipment, a cost of sending a first data to a first base station a first round trip time (RTT); estimating at the user equipment the second round trip time it takes to send the second data to the second base station; and at the user equipment based on the first round trip time time and the second round-trip time to determine the size of the first data to be sent to the first base station.

According to another aspect of the inventive concept, a method for implementing multiple connections between multiple base stations and user equipment is provided. The method includes: estimating at the first base station a direction from the first base station to the user equipment. a first round trip time taken by the user equipment to send the first data; obtaining at the first base station a second round trip time taken from the second base station to send the second data to the user equipment; and at the first base station The size of the first data to be sent from the first base station to the user equipment is determined based on the first round trip time and the second round trip time.

According to another aspect of the inventive concept, a method for implementing multiple connections between a plurality of base stations and a user equipment is provided, the method comprising: estimating a connection between the plurality of base stations and the user equipment via Multiple round-trip times (RTTs) taken by multiple channels to send data and receive acknowledgment responses (ACKs); obtain respective channel bandwidths of the multiple channels; and based on the multiple round-trip times and the channel bandwidths Determine the size of multiple pieces of segmented data to be sent via the multiple channels.

FIG. 1 is a diagram illustrating multiple connections according to an exemplary embodiment. In detail, FIG. 1 is a diagram showing multiple wireless communication systems. The multiple wireless communication systems include a first wireless communication system RAT1 and a third wireless communication system RAT1 which respectively include user equipment (UE) 30 and multiple base stations. 2. Wireless communication system RAT2, the plurality of base stations include a first base station 10 and a second base station 20.

In a non-limiting embodiment, each of the first wireless communication system RAT1 and the second wireless communication system RAT2 may be a fifth generation ( ^5th generation, 5G) system or a fifth generation new radio (5G new radio, 5G NR) system, long term evolution (LTE) system, code division multiple access (CDMA) system, global system for mobile communication (GSM) system, wireless area network ( wireless local area network (WLAN) system or another any wireless communication system. In this article, the wireless communication system may be called radio access technology (RAT).

The first base station 10 and the second base station 20 can communicate with the UE 30 based on multiple connections. For example, as shown in FIG. 1 , the UE 30 and the first base station 10 can establish a first channel CH1 according to the first wireless communication system RAT1 and can communicate with each other via the first channel CH1. The UE 30 and the second base station 20 may be established according to the second wireless communication system RAT2 and may communicate with each other via the second channel CH2. In some embodiments, the first wireless communication system RAT1 may be the same as the second wireless communication system RAT2. In some other embodiments, the first wireless communication system RAT1 may be different from the second wireless communication system RAT2. In the following, in an exemplary embodiment, it will be mainly explained that the first wireless communication system RAT1 is a 5G NR system (ie, the first base station 10 is a 5G NR base station) and the second wireless communication system RAT2 is an LTE system (ie, the first base station 10 is a 5G NR base station). The second base station 20 is an example of an LTE base station). However, it should be understood that the exemplary embodiments are not limited thereto.

A base station (for example, the first base station 10 and/or the second base station 20) may represent a fixed station and may communicate with the UE 30 and/or another base station to exchange data and control information. For example, a base station may be called a node B, an evolved node B (eNB), a next-generation node B (gNB), a sector, a site, or a base transceiver system. (base transceiver system, BTS), access point (access point, AP), relay node (relay node), remote radio head (RRH), radio unit (radio unit, RU) or small cell ( small cells). In this article, a base station or cell can be regarded as represented by a base station controller (BSC) in CDMA, a Node B in wideband code division multiple access (WCDMA), and an eNB in LTE. Or the comprehensive meaning of the functions performed by gNB or magnetic area (website) in 5G NR or the specific area covered, and can cover, for example, the following various coverage areas: mega cell, micro cell, pico Cell (pico cell), femto cell (femto cell), relay node, RRH, RU and small cell communication range.

UE 30 may be a wireless communication device and may be fixed or mobile. In addition, UE 30 may represent various devices that communicate with the base station to send or receive data and/or control information. For example, the UE 30 may be called a terminal device, a mobile station (MS), a user terminal (UT), a subscriber station (SS), a wireless device or a handheld device. In addition, the UE 30 may support multiple connections, and therefore, as shown in FIG. 1 , the UE 30 may be connected to two or more base stations, such as the first base station 10 and the second base station 20 . Specifically, as shown in FIG. 1 , one UE 30 connecting to two base stations (for example, the first base station 10 and the second base station 20 ) may be called dual connectivity. Hereinafter, in exemplary embodiments, dual connectivity will be mainly explained, but it should be understood that the exemplary embodiments are applicable to multi-connectivity in which the UE 30 communicates with three or more base stations.

The wireless communication network between the first base station 10 and the second base station 20 and the UE 30 can share available network resources, and therefore, can support multiple users. For example, information can be transmitted over a wireless communication network using multiple access schemes such as: CDMA, frequency division multiple access (FDMA), time division multiple access, TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM)-FDMA, OFDM-TDMA and OFDM-CDMA. The first base station 10 can communicate with the second base station 20 through the interface IF. In some embodiments, the first base station 10 can access the second base station 20 through a twice (X2) interface. In some other embodiments, as described below with reference to Figure 12, the first base station 10 may access the second base station 20 via the core network.

In the multi-connection, the data can be divided and sent, and the divided portions of the data (eg, the first data and the second data) can be sent via the first channel CH1 and the second channel CH2 respectively. For example, in the downlink, the first base station 10 and the second base station 20 may transmit the first data and the second data obtained by dividing the data to be sent to the UE 30 through the first channel CH1 and the second channel. Channel CH2 is sent to UE 30 respectively. In addition, in the uplink, the UE 30 can divide the data to be sent into first data and second data, and can send the first data and the second data to the first base station via the first channel CH1 and the second channel CH2 respectively. 10 and the second base station 20. Hereinafter, according to an exemplary embodiment, as described below with reference to the drawings, the UE 30 and the first and second base stations 10 and 20 may efficiently operate based on the status of each of the first channel CH1 and the second channel CH2. Split data. Therefore, delays caused by reordering data can be reduced, and users of UE 30 can be provided with improved quality of experience (QoE).

FIG. 2 is a diagram illustrating the structure of a wireless protocol in the multi-connection shown in FIG. 1 according to an exemplary embodiment.

As described above with reference to FIG. 1, the UE 30' can access the first base station 10' and the second base station 20'. In Figure 2, it can be assumed that the first base station 10' is a base station of the 5G NR system (eg, gNB), and the base station 20' is a base station of the LTE system (eg, eNB). As shown in Figure 2, the UE 30' (or the packet data convergence protocol (PDCP) of the UE 30') can support the wireless protocol of the first wireless communication system RAT1 (for example, the 5G NR system) and the second wireless communication system. Wireless protocol for communication systems RAT2 (e.g. LTE system). In the following, FIG. 2 will be explained with reference to FIG. 1 .

Referring to Figure 2, in each of the first base station 10' and the UE 30', the wireless protocol of the first wireless communication system RAT1 may include physical (PHY) layers 11 and 31a, medium access control (medium access) control, MAC) 12 and 32a, radio link control (radio link control, RLC) 13 and 33a, and PDCP 14 and 34. Each of the PHY layers 11 and 31a, MAC 12 and 32a, RLC 13 and 33a, and PDCP 14 and 34 can perform its unique function based on the provisions of the first wireless communication system RAT1. For example, the PHY layers 11 and 31a can encode and modulate the data of the MAC 12 and 32a, generate OFDM symbols, and send the generated OFDM symbols to the first channel CH1, and the OFDM symbols received through the first channel CH1 Demodulates and decodes, and transmits the data to MAC 12 and 32a. MAC 12 and 32a can implement functions including hybrid automatic repeat request (HARQ) retransmission, RLC 13 and 33a can implement functions including automatic repeat request (ARQ), and PDCP 14 and 34 implements functionality including reordering.

In each of the second base station 20' and the UE 30', the wireless protocol of the second wireless communication system RAT2 may include PHY layers 21 and 31b, MAC 22 and 32b, RLC 23 and 33b, and PDCP 24 and 34. Each of the PHY layers 21 and 31b, MAC 22 and 32b, RLC 23 and 33b, and PDCP 24 and 34 can perform its unique function based on the provisions of the second wireless communication system RAT2. For example, the PHY layers 21 and 31b can encode and modulate the data of the MAC 22 and 32b, generate OFDM symbols, and send the generated OFDM symbols to the second channel CH2. Demodulate and decode, and transmit the data to MAC 22 and 32b. MAC 22 and 32b may perform functions including HARQ retransmission, RLC 23 and 33b may perform functions including ARQ, and PDCP 24 and 34 may perform functions including reordering.

PDCP 34 may include split bearer in dual connectivity. Split bearers can distribute data packets to multiple different RLC entities in a PDCP to send data via multiple channels, and therefore, can represent a data radio bearer used to increase the data transmission rate. , DRB). For example, in the uplink, PDCP 34 may process the data packet (or PDCP service data unit (SDU)) into a PDCP protocol data unit (PDU) and may transmit the PDCP PDU to Two RLC entities 33a and 33b. Here, when the PDCP PDUs transmitted to the two RLC entities 33a and 33b are not properly distributed (ie, when the size of the segmented data is not properly determined), the delay caused by the reordering in the PDCP 34 may Increase. When delays due to reordering increase, delays may occur in the upper layers of PDCP 34, such as the application layer (eg, 35 shown in Figure 3), thereby degrading the user QoE of UE 30'. Additionally, problems similar to those described above may occur in the downlink.

FIG. 3 is a diagram showing the structure of a wireless protocol in the UE 30'' according to an exemplary embodiment. In detail, Figure 3 shows the structure of the wireless protocol in the uplink. Hereinafter, FIG. 3 will be explained with reference to FIG. 1 , and in explaining FIG. 3 , descriptions that are the same or similar to those previously provided with reference to FIG. 2 will be omitted.

Referring to FIG. 3 , the wireless protocol may include a first PHY layer 31a', a first MAC 32a' and a first RLC 33a' of the first wireless communication system RAT1, and may include a second PHY layer 31b' of the second wireless communication system RAT2. , the second MAC 32b' and the second RLC 33b', and the PDCP 34' can support the first wireless communication system RAT1 and the second wireless communication system RAT2. Additionally, an application 35 corresponding to an upper layer of the PDCP 34' may provide the PDCP 34' with data packets to be sent via the uplink.

As described above with reference to FIG. 2, PDCP 34' may determine the data (eg, the size of the first data and the size of the second data) to be sent via the first channel CH1 and the second channel CH2 in the multi-connection, and therefore, The data packet provided from the application 35 may be segmented and multiple pieces of segmented data may be provided to the first RLC (or first RLC entity) 33a' and the second RLC (or second RLC entity) 33b' respectively. For example, according to the recently released NR PDCP standard (3GPP TS 38.323 V15.2.0, 2018-06), the means to minimize the PDCP reordering delay caused by the data splitting operation performed by the UE 30'' is defined as UE 30 ''Ability.

In some embodiments, a plurality of indicators may be provided to the PDCP 34' from lower layers, and data may be distributed to the first RLC 33a' and the second RLC 33b' based on the plurality of indicators. For example, as shown in Figure 3, the first indicator IND1 may be provided to the PDCP 34' from the first PHY layer 31a', the first MAC 32a' and the first RLC 33a', and the first indicator IND1 may be provided from the second PHY layer 31b' , the second MAC 32b' and the second RLC 33b' provide the second indicator IND2 to the PDCP 34'. The PDCP 34' may detect the status of the first channel CH1 and the status of the second channel CH2 based on the first indicator IND1 and the second indicator IND2, and may transfer the data based on the status of the first channel CH1 and the status of the second channel CH2. Distributed to the first RLC 33a' and the second RLC 33b'. Exemplary operations of PDCP 34' will be explained below with reference to FIG. 4 .

4 is a flowchart illustrating a method for implementing multiple connections according to an exemplary embodiment. For example, the method shown in FIG. 4 may be performed by the PDCP 34' shown in FIG. 3, and as described below with reference to FIG. 5, the method shown in FIG. 4 may be triggered by various factors. In the following, FIG. 4 will be explained with reference to FIGS. 1 and 3 .

Referring to Figure 4, in , an operation of estimating round trip time may be performed. Round trip time (RTT) can be defined as the time it takes for a sender to send data to a receiver and to receive a response (for example, an acknowledgment response (ACK)) from the receiver for the sent data. Document "Stability of end-to-end algorithms for joint routing and rate control" (F. Kelly and T. Valls) (T. Voice), Association for Computing Machinery Special Interest Group on Data Communication Computer Communication Review (ACM SIGCOMM CCR), 35, 2005) has been proposed to use the transmission control protocol (transmission control protocol (TCP), and the proposed method can be expressed as the following equation (1). The sender can change the congestion window (congestion window) "cwnd" of the corresponding path through Δw _p in the following equation (1): (1)

In equation (1), P may represent the total set of paths formed by a single host, w _i may represent the current sending window of the i-th path, and RTT _i may represent the round-trip time of the i-th path. In some embodiments, in multiple connections, segmentation of data may be performed based on changes to the send window provided in equation (1). In TCP, the round-trip time can be determined based on the traffic volume of the network, and therefore, the sender can measure the difference between the time when the data is sent and the time when the ACK is received as the round-trip time. On the other hand, in multi-connection, the round trip time can depend on the status of the channel and can be estimated as described below.

To apply equation (1) to the multi-connection shown in Figure 1, the first round trip time RTT ₁ and the second round trip time RTT ₂ corresponding to the first channel CH1 and the second channel CH2 respectively can be estimated. For example, as described above with reference to FIG. 3 , the PDCP 34 ′ of the UE 30 ″ may estimate the first round trip time RTT _{1 based on the first indicator ID1 provided from the lower layer, and may estimate the first round trip time RTT 1} based on the first indicator ID1 provided from the lower layer. The second indicator ID2 is used to estimate the second round trip time RTT ₂ . An example of operation S200 will be explained below with reference to FIG. 6 .

In operation S400, an operation of obtaining the channel bandwidth may be performed. As shown in FIG. 1 , in a multi-connection in which the UE 30 communicates with the first base station 10 and the second base station 20 , the UE 30 and one base station (eg, the first base station 10 or the second base station 20 ) may be regarded as a single base station. 1-hop network, and w _i of Equation (1) can be expressed as the multiplication of channel bandwidth and round-trip time as in Equation (2) below: (2)

_Therefore , in equation (1), _{" BW i} And the operation of the second channel bandwidth BW ₂ ) of the second channel CH2. For example, the first PHY layer 31a' and the second PHY layer 31b' can measure the first channel bandwidth BW ₁ and the second channel bandwidth BW ₂ respectively, and the PDCP 34' can measure the first channel bandwidth BW 1 and the second channel bandwidth BW 2 based on the first indicator IND1. The first channel bandwidth BW ₁ is obtained based on the indicator provided by the PHY layer 31a', and the second channel bandwidth _BW2 can be obtained based on the indicator provided from the second PHY layer 31b' in the second indicator IND2.

In operation S600, an operation of determining sizes of multiple pieces of divided data (eg, first data and second data) may be performed. When the first channel bandwidth BW ₁ and the second channel bandwidth BW ₂ respectively correspond to the channel bandwidth of the first channel CH1 and the channel bandwidth of the second channel CH2, in the multi-connection shown in Figure 1, equation (1) can be expressed as the following equation (3): (3)

Furthermore, in multi-connection based on the number of channels M (where M is an integer greater than one), Equation (1) can be expressed as the following Equation (4): (4)

The first round trip time RTT ₁ and the second round trip time RTT ₂ may be estimated in operation S200, and the first channel bandwidth BW ₁ and the second channel bandwidth BW ₂ may be obtained in operation S400. Therefore, in operation S600, the PDCP 34' may calculate the change in data size (ie, Δw) based on equation (3), and may reflect the change Δw in the segmentation of the data packet to be sent. An example of operation S600 will be explained below with reference to FIG. 8 .

FIG. 5 is a flowchart illustrating a method for implementing multiple connections according to an exemplary embodiment. Specifically, the execution of the method for implementing multiple connections described above with reference to FIG. 4 may be triggered in operation S100 shown in FIG. 5 , and after execution of operation S100 , operation S200 shown in FIG. 4 may be executed sequentially. In addition, after the operation S600 shown in FIG. 4 is performed, the operation S100 shown in FIG. 5 may be performed. As shown in FIG. 5 , operation S100 may include operations S120, S140, and S160. In some embodiments, when at least one of operations S120, S140, and S160 of operation S100 is performed, the method may continue to operation S200. In some other embodiments, operation S100 may include only some of operations S120, S140, and S160. In the following, FIG. 5 will be explained with reference to FIG. 3 .

In operation S120, an operation of receiving a data packet may be performed. For example, when receiving a data packet from the application 35 corresponding to the upper layer, the PDCP 34' may trigger the method shown in Figure 4. The data packet received from the application 35 may be data to be sent by the application 35 through wireless communication and may be called a PDCP SDU, and in some embodiments, the data packet may include a header and a payload.

In operation S140, an operation of receiving ACK may be performed. For example, when receiving an ACK corresponding to an RLC PDU in RLC acknowledgment mode (AM), PDCP 34' may trigger the method shown in Figure 4. In some embodiments, PDCP 34' may trigger the method shown in Figure 4 when a predefined number of ACKs are received. Additionally, in some embodiments, as described below with reference to Equation (8), PDCP 34' may trigger the method shown in Figure 4 based on a predefined period or another factor, and in this case, the received The number of ACKs.

In operation S160, an operation of receiving updated retransmission parameters may be performed. As described below with reference to FIG. 6 , the round-trip time may be estimated based on retransmissions in operation S200 shown in FIG. 4 . The wireless communication system can specify the value of the retransmission parameter. Some wireless communication systems (eg, 5G NR system) can specify the value change of the retransmission parameter, and the base station can update the retransmission parameter based on the channel status. When the value of the retransmission parameter changes, the estimated round-trip time may change, and therefore, when updated retransmission parameters are received from the base station, PDCP 34' may trigger the method shown in Figure 4.

FIG. 6 is a flowchart illustrating operation S200 shown in FIG. 4 according to an exemplary embodiment. As described above with reference to FIG. 4 , the operation of estimating the round trip time may be performed in operation S200 ′ shown in FIG. 6 . Specifically, in operation S200' shown in FIG. 6, a round trip time corresponding to one channel can be estimated, and the operation S200' shown in FIG. 6 can be performed multiple times sequentially or in parallel based on multiple channels. As shown in FIG. 6 , operation S200' may include operation S220 and operation S240. In the following, FIG. 6 will be explained with reference to FIGS. 1 and 3 , and the estimation of the first round trip time RTT 1 corresponding to the first channel CH1 will be explained based on the assumption that the UE 30 shown in FIG. 1 is the UE 30 ″ shown in FIG. ₃ instance.

In operation S220, an operation of obtaining retransmission parameters may be performed. For example, the PDCP 34' may be provided with a first indicator IND1 provided from the first base station 10, the first indicator IND1 including a first retransmission parameter. In some embodiments, PDCP 34' may reflect HARQ retransmissions in the estimate of the first round trip time RTT ₁ , and for example, the first retransmission parameters may include retransmission period c ₁ and the maximum number of retransmissions N ₁ . In some other embodiments, PDCP 34' may reflect RLC retransmissions in the estimate of the first round trip time _RTT1 , and for example, the first retransmission parameter may include an RLC maximum retransmission number _R1 .

In operation S240, an operation of calculating the round trip time may be performed. For example, the PDCP 34' may calculate the first round trip time RTT ₁ based on the retransmission parameter obtained in operation S220, and the first round trip time RTT ₁ is used to calculate the change in data size Δw in equation (3). In some embodiments, PDCP 34' may calculate the round-trip time including HARQ retransmissions provided by the first MAC 32a'. In some embodiments, PDCP 34' may calculate a round trip time that also includes RLC retransmissions provided by the first RLC 33a'. An example of operation S240 will be described below with reference to FIGS. 7A and 7B.

7A and 7B are flowcharts illustrating operation S240 shown in FIG. 6 according to an exemplary embodiment.

The operation of calculating the first round trip time RTT ₁ as explained above with reference to FIG. 6 may be performed in operation S240a shown in FIG. 7A and operation S240b shown in FIG. 7B. When describing the embodiment shown in FIG. 7A and FIG. 7B , repeated description will be omitted. 7A and 7B will be explained with reference to FIGS. 1 and 3 , and the estimation of the first round trip time RTT 1 corresponding to the first channel CH1 based on the assumption that the UE 30 shown in FIG. 1 is the UE 30 ″ shown in FIG. ₃ will be explained. Example.

Referring to FIG. 7A , operation S240a may include operations S242a and S244a, and in operation S242a, an operation of calculating a round-trip time including HARQ retransmission may be performed. For example, PDCP 34' may calculate the first round trip time RTT _S1 including HARQ retransmission using the block error rate BLER as in equation (5) below: (5)

In equation (5), the first block error rate BLER ₁ may represent the block error rate measured in the first channel CH1. In some embodiments, the PDCP 34' may obtain the first block error rate _BLER1 from the indicator provided by the first PHY layer 31a' in the first indicator IND1.

The first propagation delay p ₁ may represent the propagation delay occurring in the first channel CH1. In some embodiments, PDCP 34' may obtain first propagation delay p ₁ from first MAC 32a'. For example, the first base station 10 may allocate a dedicated random access preamble to the UE 30'', and when the UE 30'' does not include a preamble for first accessing the first base station 10 or for transmitting the signal When sending to the radio resources of the first base station 10, the UE 30'' may perform a random access procedure (RACH) based on the random access preamble. The first base station 10 may use the random access preamble (or sounding reference signal (SRS)) to measure the transmission time of the UE 30'', calculate the correction timing value, and notify the UE 30'' of the calculated correction timing. value. The corrected timing value (ie, timing advance value) provided from the first base station 10 to the UE 30 ″ may be called a timing advance command (TAC), and the TAC may be processed in the MAC layer. Therefore, the first MAC 32a' of the UE 30' may generate the first propagation delay p ₁ based on the TAC and may provide the first propagation delay p ₁ to the PDCP 34' as one of the first indicators IND1.

In some embodiments, the first propagation delay p ₁ may be omitted in the calculation of the first round trip time RTT _S1 including HARQ retransmission. For example, in Equation (5), the first propagation delay p ₁ may have a smaller value than 'n1×c1', and therefore, the first propagation delay including HARQ retransmission may be calculated as in Equation (6) below. Round trip time RTT _S1 . In this case, the operation of obtaining the first propagation delay p ₁ as the first retransmission parameter from the first MAC 32a' may be omitted in operation S220 shown in FIG. 6 . (6)

In some embodiments, the PDCP 34' may determine the first round trip time RTT _S1 as the first propagation delay p ₁ in RLC unacknowledged mode (UM). For example, when maintaining the first block error rate BLER ₁ approximately at zero, RLC UM may be set, and PDCP 34' may determine the first round trip time RTT _S1 as the first propagation delay p ₁ . Additionally, in some other embodiments, PDCP 34' may reflect changes Δw every first propagation delay p ₁ (ie, first round trip time RTT _S1 ).

It should be understood that the second round trip time RTT _S2 including HARQ retransmission and corresponding to the second channel CH2 is similarly calculated based on Equation (5) and/or Equation (6).

In operation S244a, an operation of calculating a round trip time including RLC retransmission may be performed. For example, PDCP 34' may calculate the first round trip time RTT _T1 including RLC retransmission as in equation (7) below: (7)

In the embodiment shown in FIG. 7A , the PDCP 34' may use the first round trip time RTT _T1 calculated based on Equation (7) as the data change Δw of Equation (3). In addition, it should be understood that the second round trip time RTT _S2 including HARQ retransmission and corresponding to the second channel CH2 is similarly calculated based on equation (7).

Referring to FIG. 7B , operation S240b may include operation S242b, operation S243b, and operation S244b. Compared with operation S240a shown in FIG. 7A , operation S240b shown in FIG. 7B may further include operation S243b. Similar to operation S242a shown in FIG. 7A, an operation of calculating a round-trip time including HARQ retransmission may be performed in operation S242b. Therefore, the first round trip time RTT _S1 and the second round trip time RTT _S2 respectively including HARQ retransmission can be calculated.

In operation S243b, an operation of comparing the block error rate BLER with the predefined first threshold THR1 may be performed. For example, in the process of calculating the first round trip time RTT _S1 , the first block error rate BLER ₁ can be compared with the predefined first threshold THR1, and as shown in Figure 7B, when the first block error When the rate _BLER1 is less than the first threshold THR1, operation S240b may end. On the other hand, when the first block error rate _BLER1 is equal to or greater than the first threshold THR1, operation S244b may be performed, and in operation S244b, an operation of calculating the first round trip time RTT _T1 including the RLC retransmission may be performed.

Therefore, in the embodiment shown in FIG. 7B , when the first block error rate BLER ₁ is less than the first threshold THR1 , the first round trip time RTT _S1 including HARQ retransmission of equation (5) or equation (6) can be It is determined as the final first round trip time RTT ₁ . On the other hand, when the first block error rate BLER ₁ is equal to or greater than the first threshold THR1 , the first round trip time RTT _T1 including the RLC retransmission may be determined as the final first round trip time RTT ₁ . In a state where the block error rate is low, the likelihood of an RLC retransmission may be low, and therefore, in the embodiment shown in FIG. 7B , operation S244b (eg, calculation based on Equation (7)) may be omitted .

FIG. 8 is a flowchart illustrating operation S600 shown in FIG. 4 according to an exemplary embodiment. As described above with reference to FIG. 4 , in operation S600 ′ shown in FIG. 8 , an operation of determining the sizes of multiple pieces of divided data (eg, first data and second data) may be performed. As shown in FIG. 8 , operation S600' may include operation S620 and operation S640. In the following, FIG. 8 will be explained with reference to FIGS. 3 and 4 .

In operation S620, an operation of calculating changes in data size may be performed. For example, the change in data size Δw may be calculated as in equation (3) based on the round trip time obtained through operation S200 and the channel bandwidth obtained through operation S400. In some embodiments, the variation Δw may apply equally to multiple channels.

In some embodiments, when the change in data size is not calculated every time an ACK occurs, the change in data size Δw ₁ corresponding to the first channel CH1 can be calculated as in the following equation (8): (8)

In Equation (8), N _ACK1 may represent the number of ACKs received from the first base station 10 via the first channel CH1. For example, the PDCP 34' may calculate the change in data size Δw ₁ in the RLC AM based on Equation (8). Similarly, the change Δw ₂ in the data size corresponding to the second channel CH2 may be calculated using N _{ACK2 ,} which represents the number of ACKs received from the second base station 20 via the second channel CH2 .

In a multi-connection based on M number of channels, the change Δw _i corresponding to the data size of the i-th channel CHi can be calculated as in the following equation (9): (9)

In operation S640, an operation of changing the data size may be performed. For example, the PDCP 34' may add the change Δw calculated by operation S620 to the data size set in multiple channels to change the data size. In some embodiments, when the change Δw applies equally to the multiple channels, the same change Δw may be added to the data size set in the multiple channels. For example, retransmissions may occur rarely in channels with sufficient quality, and therefore, even when the variation Δw has a negative value, a channel with sufficient quality (or channel status) channel to send large amounts of data. In addition, retransmissions can occur frequently in channels with poor quality, and therefore, even when the variation Δw has a positive value, a small amount of data can still be sent via a channel with lower quality compared to a channel with sufficient quality .

9A and 9B are flowcharts illustrating operation S640 shown in FIG. 8 according to an exemplary embodiment. In detail, operation S640a shown in FIG. 9A and operation S640b shown in FIG. 9B may respectively include operations S644a and S644b of blocking data transmission via a channel with a bad channel status. As described below with reference to FIG. 8, the operation of changing the data size may be performed in operation S640a shown in FIG. 9A and operation S640b shown in FIG. 9B. Hereinafter, repeated description will be omitted when explaining FIGS. 9A and 9B , and FIGS. 9A and 9B will be explained with reference to FIG. 3 .

Referring to FIG. 9A, operation S640a may include operations S641a to S646a, and an initialization operation may be performed in operation S641a. For example, as shown in FIG. 9A , the variable i representing the index of the channel may be set to 1. In the embodiment shown in FIG. 9A, the sizes of the plurality of pieces of data to be sent via M number of channels may be determined, and therefore, the variable i may have a value of "1 to M".

In operation S642a, an operation of comparing the block error rate BLER _i of the i-th channel with the predefined second threshold THR2 may be performed. As shown in FIG. 9A , when the block error rate BLER _i of the i-th channel is greater than the second threshold THR2, operation S644a may be performed, and in operation S644a, the operation of determining the data size to zero may be performed. On the other hand, when the block error rate BLER _i of the i-th channel is equal to or less than the second threshold THR2, operation S643a may be performed, and in operation S643a, the operation of reflecting the change in the data size in the data distribution may be performed. Therefore, when the block error rate BLER of a channel is high, the PDCP 34' can block sending data through the corresponding channel.

In operation S645a, an operation of comparing the variable i with M may be performed. As shown in FIG. 9A, when variable i does not match M (ie, when variable i is less than M), variable i may be increased by one in operation S646a, and operation S642a may be performed again. On the other hand, when the variable i matches M (that is, when the data sizes corresponding to the M channels are all determined), operation S640a may end.

Referring to FIG. 9B, operation S640b may include operations S641b to S646b. Operations similar to operations performed in some of the operations S641a and S643a to S646a shown in FIG. 9A may be performed in some of the operations S641b and S643b to S646b shown in FIG. 9B.

In operation S642b, an operation of comparing the predefined threshold THR3 with the rate NACK% of a negative unacknowledge response (NACK) occurring in the i-th channel may be performed. As shown in FIG. 9B , when the rate NACK% of NACK occurring in the i-th channel is higher than the threshold THR3, operation S644b may be performed, and when the rate NACK% of NACK occurring in the i-th channel is equal to or lower than the threshold THR3, Operation S643b can be performed. Therefore, when the NACK ratio NACK% of a channel is high, PDCP 34' may block sending data through the corresponding channel.

Figure 10 is a block diagram illustrating a UE 100 according to an exemplary embodiment. As described above with reference to FIG. 1 , the UE 100 shown in FIG. 10 can support multiple connections and can perform wireless communication with two or more base stations. As shown in FIG. 10 , the UE 100 may include an antenna 110, a transceiver 120, a data processor 130, a memory 140 and a main processor 150. The elements of UE 100 are shown independently in Figure 10, but in some embodiments, two or more elements may be implemented as one entity (eg, a semiconductor wafer).

The antenna 110 may receive radio frequency (RF) signals from the base station, or may transmit RF signals to the base station. In some embodiments, the antenna 110 may be configured as an antenna array including multiple antennas and may support multiple input multiple output (MIMO) and beamforming.

The transceiver 120 can process signals between the antenna 110 and the data processor 130 . For example, transceiver 120 may include dual multiplexers, switches, filters, multiplexers, and amplifiers. In addition, the transceiver 120 may process the radio frequency signal received through the antenna 110 to generate the received signal RX and may provide the received signal RX to the data processor 130 . In addition, the transceiver 120 may process the transmission signal TX provided from the data processor 130 to generate a radio frequency signal and may provide the generated radio frequency signal to the antenna 110 . In some embodiments, the transceiver 120 may be referred to as a radio frequency integrated circuit (RFIC).

The data processor 130 may process the data packet PKT received from the main processor 150 to generate the transmit signal TX, process the receive signal RX received from the transceiver 120 to generate the data packet PKT, and convert the generated data packet PKT provided to main processor 150. The data processor 130 may perform operations corresponding to at least one layer in the wireless protocol architecture. For example, the data processor 130 may be called a communication protocol and may implement the first PHY layer 31a' and the second PHY layer 31b', the first MAC 32a' and the second MAC 32b', and the first RLC shown in Figure 3 33a' and the functions of the second RLC 33b' and PDCP 34'. In some embodiments, the data processor 130 may include hardware, a processing unit, and a combination of hardware and processing units. The hardware includes logical blocks designed based on logical combinations. The processing unit includes software and a processor for executing the software. At least one core (or at least one processor). For example, the data processor 130 may include the first PHY layer 31a' and the second PHY layer 31b', the first MAC 32a' and the second MAC 32b', the first RLC 33a' and the second PHY layer shown in FIG. 3 respectively. The hardware blocks and/or software blocks corresponding to RLC 33b' and PDCP 34'. The method according to the exemplary embodiments set forth above with reference to the drawings and at least one operation included in the method may be performed by the data processor 130 . In some embodiments, a base station (eg, 10 and/or 20 shown in FIG. 1) may have a structure similar to that of the UE 100 shown in FIG. 10, and a data processor included in the base station may be implemented to implement dual A method of connection and at least one operation included in said method.

The memory 140 may store data required for the processing performed by the data processor 130 and may store signals and/or data. In some embodiments, memory 140 may store software (ie, a sequence of instructions) executed by data processor 130 .

The main processor 150 may include at least one core (or processor). In addition, the main processor 150 may transmit the data packet PKT to be sent through wireless communication to the data processor 130 and may receive data sent from the base station based on the data packet PKT provided from the data processor 130 . The main processor 150 may control the operation of the UE 100 and may generate data packets PKT or may perform operations based on the received data packets PKT.

11A and 11B are diagrams illustrating a method for implementing multiple connections with respect to time streams according to an exemplary embodiment. In detail, FIGS. 11A and 11B are diagrams illustrating an example of a method for implementing multiple connections in downlink. In some embodiments, one of the base stations connected to the UE may perform segmentation of data for multiple connections, and the first base stations 10a and 10b (i.e., the base stations of the 5G NR system) will be described below with reference to FIGS. 11A and 11B (e.g., gNB)) implements an instance of partitioning of data for multiple connections. However, it should be understood that the exemplary embodiments are not limited thereto. In the following, FIGS. 11A and 11B will be explained with reference to FIG. 1 , and it can be assumed that the first base station 10 , the second base station 20 and the UE 30 shown in FIG. 1 correspond to the first base station 10 a , the second base station 20 a and the UE shown in FIG. 11A 30a and corresponds to the first base station 10b, the second base station 20b and the UE 30b shown in Figure 11B. When describing FIGS. 11A and 11B , repeated description will be omitted.

Referring to FIG. 11A , the second round trip time RTT ₂ corresponding to the second channel CH2 may be estimated by the second base station 20a that establishes the second channel CH2 together with the UE 30a, and the estimated second round trip time RTT ₂ may be derived from the second The base station 20a provides the first base station 10a.

In operation S11a, the first base station 10a may estimate the first round trip time RTT ₁ . The first base station 10a may establish the first channel CH1 with the UE 30a, and therefore, as described above with reference to the figures, the first base station 10a may estimate the first round trip time RTT 1 in a manner similar to the manner in which the first round trip time RTT ₁ is estimated by the UE 30a The first round trip time RTT ₁ . In addition, in operation S12a, the first base station 10a may obtain the first channel bandwidth BW ₁ .

In operation S13a, the second base station 20a may estimate the second round trip time RTT ₂ . The second base station 20a may establish the second channel CH2 with the UE 30a, and therefore, as described above with reference to the figures, the second base station 20a may estimate the second round trip time RTT 2 in a manner similar to the manner in which the second round trip time RTT ₂ is estimated by the UE 30a The second round trip time RTT ₂ . In addition, in operation S14a, the second base station 20a may obtain the second channel bandwidth BW ₂ .

In operation S15a, the second base station 20a may provide the second round trip time RTT ₂ and the second channel bandwidth BW ₂ to the first base station 10a. For example, as described above with reference to FIG. 1 , the second base station 20a may provide the second round trip time RTT ₂ and the second channel bandwidth BW ₂ to the first base station 10a via the interface IF.

In operation S16a, the first base station 10a may calculate the data size. For example, in operations S11a to S15a, the first base station 10a may collect information about the first channel CH1 and the second channel CH2 and may calculate the change in data size Δw based on the collected information as in equation (3) . The first base station 10a may reflect the change in data size Δw in the size of the first data to be sent from the first base station 10a to the UE 30a and to the size of the second data to be sent from the second base station 20a to the UE 30a. Calculating.

In operation S17a, the first base station 10a may transmit the first material to the UE 30a via the first channel CH1 based on the calculated size of the first material. In addition, in operation S18a, the first base station 10a may provide the second data to the second base station 20a. In operation S19a, the second base station 20a may transmit the second material provided from the first base station 10a to the UE 30a via the second channel CH2.

Referring to FIG. 11B , the second base station 20b that establishes the second channel CH2 together with the UE 30b may provide information about the second channel CH2 to the first base station 10b, and the first base station 10b may estimate the second channel CH2 based on the information about the second channel CH2. 2. Round trip time RTT ₂ .

In operation S11b, the first base station 10b may estimate the first round trip time RTT ₁ , and in operation S12b, the first base station 10b may obtain the first channel bandwidth BW ₁ .

In operation S13b, the second base station 20b may provide the second channel information to the first base station 10b. For example, as described above with reference to the figures, the second base station 20b may provide the first base station 10b with information for estimating the second round trip time RTT ₂ (for example, the second retransmission parameter corresponding to the second channel CH2) and information used to calculate the change in data size Δw (e.g., second channel information including second channel bandwidth BW ₂ ). In some embodiments, the second base station 20b may provide the first base station 10b with the propagation delay corresponding to the second channel CH2 (ie, the second propagation delay p ₂ ).

In operation S14b, the first base station 10b may estimate the second round trip time RTT ₂ . For example, the first base station 10b may use Equation (5), Equation (6) and/or Equation (7) to estimate the second round trip time RTT ₂ based on the second channel information provided in operation S13b.

In operation S15b, the first base station 10b may calculate the data size. In operation S16b, the first base station 10b may transmit the first material to the UE 30b via the first channel CH1 based on the calculated size of the first material. In addition, in operation S17b, the first base station 10b may provide the second data to the second base station 20b. In operation S18b, the second base station 20b may transmit the second material provided from the first base station 10b to the UE 30b via the second channel CH2.

FIG. 12 is a diagram illustrating multiple connections according to an exemplary embodiment. In detail, FIG. 12 shows a structure including cores (eg, first core and second core) 70 and 80 connected to base stations (eg, first base station and second base station) 40 and 50. Hereinafter, when explaining FIG. 12 , description repeated with FIG. 1 will be explained.

Referring to FIG. 12 , the UE 60 may access the first base station 40 via the first channel CH1 and may access the second base station 50 via the second channel CH2. The first base station 40 can access the first core 70 and the second base station 50 can access the second core 80 . For example, the first base station 40 may be a base station of a 5G NR system, and the second base station 50 may be a base station of an LTE system. In this case, the second core 80 may be called an evolved packet core (EPC).

The first core 70 and the second core 80 can access a common Internet protocol (IP) anchor 90, and the common IP anchor 90 can be a network entity and can perform data network transmission to a UE. 60 data for routing function. In some embodiments, the universal IP anchor 90 can perform data segmentation across multiple connections, and related embodiments will be described below with reference to FIGS. 13A and 13B.

13A and 13B are diagrams illustrating a method for implementing multiple connections with respect to time streams according to an exemplary embodiment. In detail, FIGS. 13A and 13B illustrate an example of a method for implementing multiple connections in downlink. In some embodiments, universal IP anchors 90a and 90b may implement partitioning of data for multiple connections, and distribution of data to the first base stations 40a and 40b of the 5G NR system and LTE will be described below with reference to Figures 13A and 13B Example of second base stations 50a and 50b of the system. However, it should be understood that the exemplary embodiments are not limited thereto.

Referring to FIG. 13A, the universal IP anchor 90a may segment the data based on the round trip time and channel bandwidth provided from the first base station 40a and the second base station 50a. In operation S21a, the first base station 40a may provide the first round trip time RTT ₁ and the first channel bandwidth BW ₁ respectively corresponding to the first channel CH1 to the universal IP anchor 90a. In operation S22a, the second base station 50a may provide the universal IP anchor 90a with the second round trip time RTT ₂ and the second channel bandwidth BW ₂ respectively corresponding to the second channel CH2. For example, the first base station 40a and the second base station 50a may respectively calculate the first round trip time RTT ₁ and the second round trip time RTT ₂ based on equation (5), equation (6) and/or equation (7).

In operation S23a, the universal IP anchor 90a may calculate the sizes of the plurality of pieces of segmented data based on the round-trip time and channel bandwidth provided from the first base station 40a and the second base station 50a. For example, the universal IP anchor 90a may calculate the change in data size Δw based on equation (3), and may reflect the change in data size Δw in the size of the first data to be sent via the first channel CH1 and the change in the data size Δw. The size of the second data to be sent via the second channel CH2 is being calculated. Subsequently, in operation S24a, the universal IP anchor 90a may provide the first material to the first base station 40a, and in operation S25a, the universal IP anchor 90a may provide the second material to the second base station 50a.

Referring to Figure 13B, universal IP anchor 90b may segment data based on channel information provided from each of first base station 40b and second base station 50b. In operation S21b, the first base station 40b may provide the first channel information corresponding to the first channel CH1 to the universal IP anchor 90b. In operation S22b, the second base station 50b may provide the second channel information corresponding to the second channel CH2 to the universal IP anchor 90b. For example, the first channel information may include a first retransmission parameter and a first channel bandwidth, and the second channel information may include a second retransmission parameter and a second channel bandwidth.

In operation S23b, the universal IP anchor 90b may estimate the round-trip time. For example, the universal IP anchor 90b may use equation (5), equation (6), and/or equation (7) to estimate the first round trip time RTT ₁ and the second round trip time RTT based on the first channel information and the second channel information. ₂ . In operation S24b, the universal IP anchor 90b may calculate the sizes of the plurality of divided data. For example, the universal IP anchor 90b may calculate the change in data size Δw based on Equation (3), and may reflect the change in data size Δw in the size of the first data to be sent via the first channel CH1 and the change in the data size Δw. The size of the second data to be sent via the second channel CH2 is being calculated. In operation S25b, the universal IP anchor 90b may provide the first material to the first base station 40b, and in operation S26b, the universal IP anchor 90b may provide the second material to the second base station 50b.

While the inventive concepts have been particularly shown and described with reference to embodiments thereof, it will be understood that various changes in form and details may be made herein without departing from the spirit and scope of the following claims. .

10, 10', 10a, 10b, 40a, 40b: the first base station 11, 21, 31a, 31b: physical layer 12, 22, 32a, 32b: Media access control 13, 23, 33a, 33b: Radio link control 14, 24, 34, 34': Packet data convergence protocol 20, 20', 20a, 20b, 50a, 50b: second base station 30, 30', 30'', 30a, 30b, 60, 100: User equipment 31a': First physical layer 31b': Second physical layer 32a': First media access control 32b': Second media access control 33a': First radio link control 33b': Second radio link control 35:Application 40: Base station/first base station 50: Base station/second base station 70:Core/First Core 80:Core/Second Core 90, 90a, 90b: Common Internet Protocol Anchors 110:Antenna 120: Transceiver 130:Data processor 140:Memory 150: Main processor CH1: first channel CH2: Second channel IF:interface IND1: first indicator IND2: Second indicator PKT: data packet RAT1: The first wireless communication system RAT2: The second wireless communication system RX: receive signal TX: send signal S11a, S11b, S12a, S12b, S13a, S13b, S14a, S14b, S15a, S15b, S16a, S16b, S17a, S17b, S18a, S18b, S19a, S21a, S21b, S22a, S22b, S23a, S23b, S24a, S24b , S25a, S25b, S26b, S100, S120, S140, S160, S200, S200', S220, S240, S240a, S240b, S242a, S242b, S243b, S244a, S244b, S400, S600, S600', S620, S640, S640a、 S640b, S641a, S641b, S642a, S642b, S643a, S643b, S644a, S644b, S645a, S645b, S646a, S646b: Operation

Embodiments of the inventive concept will be more clearly understood by reading the following detailed description in conjunction with the accompanying drawings, in which: FIG. 1 is a diagram illustrating multiple connections according to an exemplary embodiment. FIG. 2 is a diagram illustrating the structure of a wireless protocol in the multi-connection shown in FIG. 1 according to an exemplary embodiment. FIG. 3 is a diagram illustrating the structure of a wireless protocol in a user equipment according to an exemplary embodiment. 4 is a flowchart illustrating a method for implementing multiple connections according to an exemplary embodiment. FIG. 5 is a flowchart illustrating a method for implementing multiple connections according to an exemplary embodiment. FIG. 6 is a flowchart illustrating operation S200 shown in FIG. 4 according to an exemplary embodiment. 7A and 7B are flowcharts illustrating operation S240 shown in FIG. 6 according to an exemplary embodiment. FIG. 8 is a flowchart illustrating operation S600 shown in FIG. 4 according to an exemplary embodiment. 9A and 9B are flowcharts illustrating operation S640 shown in FIG. 8 according to an exemplary embodiment. Figure 10 is a block diagram illustrating user equipment according to an exemplary embodiment. 11A and 11B are diagrams illustrating a method for implementing multiple connections with respect to time streams according to an exemplary embodiment. FIG. 12 is a diagram illustrating multiple connections according to an exemplary embodiment. 13A and 13B are diagrams illustrating a method for implementing multiple connections with respect to time streams according to an exemplary embodiment.

S200, S400, S600: Operation

Claims (17)

A method for implementing multiple connections through multiple channels between multiple base stations and user equipment, the method comprising: estimating a first round trip time at the user equipment, wherein the first round trip time is The expected time it takes to send data and receive an acknowledgment through the first channel; estimate the second round-trip time at the user equipment, where the second round-trip time is the time it takes to send data and receive the acknowledgment through the second channel The expected time it takes for acknowledgment response; determining, at the user equipment, the size of the uplink data sent through the first channel based on the first round-trip time and the second round-trip time; obtaining and a first channel bandwidth corresponding to the first channel; and obtaining a second channel bandwidth corresponding to the second channel, wherein determining the size of the uplink data includes based on the first round trip time, the The second round trip time, the first channel bandwidth and the second channel bandwidth are used to obtain the size of the uplink data, wherein determining the size of the uplink data includes based on the following equation: The change in expression Δw changes the size of the uplink data:

The RTT ₁ , the RTT ₂ , the BW ₁ and the BW ₂ are respectively the first round trip time, the second round trip time, the first channel bandwidth and the second channel frequency. wide. The method as described in claim 1, wherein estimating the first round-trip time includes: obtaining a retransmission parameter corresponding to the first channel; and obtaining the first round-trip time based on the retransmission parameter. . The method as described in item 2 of the patent application, wherein the retransmission parameters include a retransmission period c ₁ and a maximum retransmission number N ₁ , and obtaining the first round trip time includes obtaining the RTT _S1 expressed in the following equation :

The BLER ₁ and the p ₁ are respectively the block error rate and the signal movement time in the first channel. The method as described in item 3 of the patent application, wherein the retransmission parameter further includes a maximum retransmission number R ₁ of the radio link control entity, and obtaining the first round trip time includes obtaining the RTT expressed in the following equation _T1 as the first round trip time:

The method of claim 3, wherein obtaining the first round-trip time includes determining the RTT _S1 as the first round-trip time in response to the BLER ₁ being less than a first threshold. The method of claim 3, wherein determining the size of the uplink data includes determining the size of the uplink data to zero in response to the BLER ₁ being greater than a second threshold. . The method according to claim 2, wherein obtaining the retransmission parameter includes obtaining an updated retransmission parameter corresponding to the first channel, and obtaining the first round-trip time includes obtaining the first round-trip time based on the updated retransmission parameter. The retransmission parameters are used to obtain the first round trip time. The method described in item 1 of the patent application, wherein the method is implemented in the packet data convergence protocol layer. The method of claim 1, wherein determining the size of the uplink data includes reducing the uplink data in response to a rate of negative non-acknowledgments through the second channel being greater than a third threshold. The stated size of the data is determined to be zero. The method described in claim 1 further includes determining the size of the uplink data sent through the second channel based on the first round trip time and the second round trip time. The method as described in item 1 of the patent application, wherein the user equipment communicates with the first base station through the first channel and communicates with the second base station through the second channel, and the first base station communicates with the first base station through the first channel and the second base station through the second channel. The second base station communicates with the user equipment based on the same radio access technology. The method as described in item 1 of the patent application, wherein the user equipment communicates with the first base station through the first channel and communicates with the second base station through the second channel, and the first base station communicates with the first base station through the first channel and the second base station through the second channel. The second base station is based on a different radio access technology. Communicate with the user equipment. A method for implementing multiple connections through multiple channels between multiple base stations and user equipment, the method comprising: estimating a first round trip time at a first base station, wherein the first round trip time is for The expected time it takes to send data through the first channel and receive the acknowledgment response; obtain the second round-trip time at the first base station, where the second round-trip time is the time it takes to send data through the second channel and receive the acknowledgment response. the expected time; determining at the first base station based on the first round-trip time and the second round-trip time the size of the downlink data to be sent from the first base station to the user equipment; obtaining the a first channel bandwidth corresponding to the first channel; and obtaining a second channel bandwidth corresponding to the second channel, wherein determining the size of the downlink data includes based on the first round trip time, the The second round trip time, the first channel bandwidth and the second channel bandwidth are used to obtain the size of the downlink data, wherein determining the size of the downlink data includes based on the following The change in Δw expressed in the equation changes the size of the downlink data:

The RTT ₁ , the RTT ₂ , the BW ₁ , the BW ₂ and the N _ACK1 are respectively the first round trip time, the second round trip time, the first channel bandwidth, the The second channel bandwidth and the number of acknowledgment responses received through the first channel. The method of claim 13, wherein obtaining the second round-trip time includes receiving from a second base station the second round-trip time estimated by the second base station. The method of claim 13, wherein obtaining the second round trip time includes: receiving channel information about the second channel from a second base station; and estimating the second round trip based on the channel information. time. A method for implementing multiple connections through multiple channels between multiple base stations and user equipment, the method comprising: estimating a first round trip time at the user equipment, wherein the first round trip time is The expected time it takes to send data and receive an acknowledgment through the first channel; estimate the second round-trip time at the user equipment, where the second round-trip time is the time it takes to send data and receive the acknowledgment through the second channel The expected time it takes to confirm the response; obtain the channel bandwidth of the first channel and the second channel; and based on the first round-trip time and the second round-trip time at the user equipment and the The channel bandwidth of the first channel and the second channel determines the size of the uplink data to be sent via the first channel and the second channel, wherein the size of the uplink data is determined. Sizing includes changing the size of the uplink data based on a change Δw expressed in the following equation:

The RTT ₁ , the RTT ₂ , the BW ₁ and the BW ₂ are respectively the first round trip time, the second round trip time, the channel bandwidth of the first channel and the The channel bandwidth of the second channel. A method for implementing multiple connections through multiple channels between multiple base stations and user equipment, the method comprising: estimating a first round trip time at the user equipment, wherein the first round trip time is The expected time it takes to send data and receive an acknowledgment through the first channel; estimate the second round-trip time at the user equipment, where the second round-trip time is the time it takes to send data and receive the acknowledgment through the second channel an expected time for acknowledgment response; and determining, at the user equipment, a size of uplink data sent through the first channel based on the first round trip time and the second round trip time, where the estimated The first round trip time includes: obtaining a retransmission parameter corresponding to the first channel; and obtaining the first round trip time based on the retransmission parameter, wherein the retransmission parameter includes a retransmission period c ₁ and a maximum The number of retransmissions is N ₁ , and obtaining the first round trip time includes obtaining the RTT _S1 expressed in the following equation:

The BLER ₁ and the p ₁ are respectively the block error rate and the signal movement time in the first channel.